Fig. 6: Mechanistic studies.

a Reaction in the presence of TEMPO (2,2,6,6-Tetramethylpiperidinooxy). b Radical clock reaction. c UV–Vis absorption spectra of Int. II and PC-3. d Stern–Volmer quenching experiments between PC-3 and sodium carboxylate 8. e Stern–Volmer quenching experiments between Int. II and sodium carboxylate 8 (black line).